Doxorubicin hydrochloride (DOX), an anthracycline antibiotic, is approved for cancer chemotherapy (O'Shaughnessy, 2003, Rose, 2005, Thotakura et al., 2021). Currently, DOX is available as an injectable formulation (2 mg/mL) marketed by Ortho Biotech Inc. (Janssen-Ortho, Bridgewater, NJ, USA) (Bladé et al., 2011, Gabizon et al., 2004, O'Shaughnessy, 2003, Rose, 2005). The chemical formula and molecular weight of DOX are C27H29NO11·HCl and 580 g/mol, respectively, and its chemical name is (7S,9S)-7-[(2R,4S,5S,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione.

In addition to belonging to the biopharmaceutical classification system (BCS) class III with a log p value of 0.53 at pH 7.0, the photosensitivity and side effects such as cardiac toxicity and mucositis of DOX are of great concern (Laxmi et al., 2019, Pinto et al., 2021, Rose, 2005, Thotakura et al., 2021). These side effects are normally relative to low drug tolerance induced by non-specific distribution and the need for high dose administration to meet therapeutic rage in the targeted cancer cell. Numerous approaches have been proposed to enhance stability and reduce side effects of DOX, such as conjugation with water-soluble polymers or dendrimers (Lee et al., 2006, Mitra et al., 2001), gold nanoparticles (Tsai et al., 2016), and liposomal drug delivery systems (DDS) (Bladé et al., 2011, Gabizon et al., 2004, O'Shaughnessy, 2003, Thotakura et al., 2021). However, when considering those reports that were not studied photostability of DOX for the intravenous administration, high costs of gold, and liposome using organic solvent, pharmaceutical technologies for enhancing the stability and reducing the side effects of DOX, which are alternatives to these complex technologies should be investigated (Mitra et al., 2001, Pranatharthiharan et al., 2017).

Nanostructured lipid carriers (NLCs), an advanced pharmaceutical formulation on the basis of solid lipid nanoparticles (SLNs), are considered promising DDS for enhancing the safety and stability of unstable drugs such as DOX. In detail, NLC and SLN are fabricated the double emulsion technique without organic solvents, which reduces toxicity of DDSs. In NLC a hydrophilic drug is entrapped in a solid–liquid mixture matrix consisting of a water-in-oil-in-water (W/O/W) phase (Bhattacharjee, 2013, Mitra et al., 2001). The solid lipid matrix physically protects the entrapped drug by structural separation from external light, which enhances photostability and eventually contributes to improving the drug stability (Dodangeh et al., 2019, Lee et al., 2006, Mitra et al., 2001, Radomska-Soukharev, 2007). In this regard, the side effects related to non-specific distribution are effectively avoided because the entrapped drugs are stably delivered without leakage (Radomska-Soukharev, 2007, Youssef et al., 2012). Moreover, a relatively low dose could be administrated by delivering a drug dose sufficient to treat the targeted cancer cell. The success of nano DDS for cancer therapy largely depends on the cellular uptake (Hu et al., 2013, Mitra et al., 2001, Nguyen et al., 2021, Teskač and Kristl, 2010). In case of oral administration as one of the proposal administrations, NLCs can deliver drug via the lymphatic system, which can bypass the liver by forming chylomicrons in enterocytes (Mitra et al., 2001, Yasir et al., 2018). Consequently, the drugs entrapped in NLCs can avoid hepatic first-pass metabolism, resulting in reduction of side effects (Jamwal, 2018, Mitra et al., 2001, Radomska-Soukharev, 2007).

In this study, DOX-loaded NLCs were designed for cancer chemotherapy to overcome the limitations of DOX. The physical characteristics of DOX and DOX-loaded NLCs were evaluated using UV–Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and particle characterization. The anticancer effect of DOX was evaluated in three tumor cell lines (HeLa from human cervical carcinoma, A549 from human lung carcinoma, and CT-26 from mouse colon carcinoma). Additionally, the pharmacological effects of DOX in these cell lines were discussed by comparing the species-specific mechanisms.